Unusual case of diagnosis of pigeon breeder's hypersensitivity pneumonitiswith ventilation-perfusion lung scan

The authors describe a patient thought to have pulmonary embolism, Results of a perfusion scan were normal, but Tc-99m DTPA aerosol ventilation lung s can showed, in successive views, decreased activity of the deposited aeroso l, The lung Tc-99m DTPA clearance was measured and was markedly increased, This suggested possible hypersensitivity pneumonitis, which was later confi rmed as pigeon breeder's disease. The decreased activity observed on the DT PA ventilation scan must be directed toward increased lung clearance and it s measurement.